Call Guard Squelch; Call Guard Squelch Enable/Disable; Selective Squelch Code Select; Penalty Timer - E.F. Johnson Company 5100 Series Operating Manual

Tone (NAC) - If the detected Call Guard or NAC
(Project 25) squelch coding is incorrect, the trans-
mitter is disabled when the PTT switch is pressed.
If Busy Channel Override is permitted by
programming, it is possible to transmit when the trans-
mitter is disabled by this feature. Simply release and
then quickly press the push-to-talk (PTT) switch again.

Call Guard Squelch

Introduction
Call Guard squelch (also called CTCSS/DCS
signaling) can be programmed on conventional analog
channels. This feature eliminates distracting messages
intended for others using the channel. This is done by
using a subaudible tone or digital code to control the
squelch. This tone or code is unique to a user or a
group on that channel, and is transmitted by the mobile
placing a call. If Call Guard squelch is programmed in
the mobile receiving the call, it must detect the correct
tone or code to receive the call.

Call Guard Squelch Enable/Disable

The Normal/Selective option key or menu param-
eter (if programmed) can be used to disable receive
Call Guard squelch so that all calls are heard. When it
is disabled, "Sq Normal" is flashed in the display, and
when it is enabled, "Sq Select" is flashed.
The receiver unsquelches only if activity is
detected on the channel, and scanning is not disabled.
The selected mode is in effect until it is manually
changed again. Selecting another channel or cycling
power does not reselect a default condition.
When this function is used on a digital channel,
talk group detect is disabled, so calls to all groups are
heard. However, the correct NAC is still detected, so
calls with another NAC are not heard (see page 19).

Selective Squelch Code Select

A different CTCSS/DCS/NAC squelch code can
be temporarily selected if the Squelch Code option key
or menu parameter and a CTCSS/NAC code list have
been programmed. This feature allows the normal
transmit and receive Call Guard programming to be
CONVENTIONAL MODE FEATURES
temporarily overridden with a code selected from this
list.
This code list is programmed with up to sixteen
CTCSS and DCS codes for use on analog channels
plus up to sixteen NAC codes for use on digital
(Project 25) channels. When a selective squelch (Call
Guard) code is changed as describe below, it remains
selected even if other channels are selected. However,
if transceiver power is cycled or a talk-around channel
is selected, the normal codes are reselected.
When scanning, the selected code also applies to
all scanned channels. If both analog and digital chan-
nels can be selected or scanned, the CTCSS/DCS code
for the selected position is used for analog channels
and the NAC code for the selected position is used for
P25 channels. Proceed as follows to select a prepro-
grammed Call Guard code:
1. Press the Selective Squelch Code option key or
select the Sqlch Code menu mode parameter. Then
press the Up/Down switch to select the desired code.
The display indicates "SEL SQ xx" where, "xx" is
the selected code from 1-16.
2. To select the displayed code and return to the normal
display, press the F2 (Select) key or the Selective
Squelch key again.
3. To check which code is selected, press the Selective
Squelch key once to display the current selection
and then again to return to normal operation.
4. To return to the normal selective squelch codes,
select "DEFAULT" in this mode. As previously
described, the normal codes are also automatically
reselected whenever transceiver power is cycled or
a talk-around channel is selected.

Penalty Timer

A penalty timer may be programmed on conven-
tional systems to prevent transmissions for the
programmed time after the time-out timer disables the
transmitter (see page 12). The penalty timer can be
programmed for the same times as the time-out timer,
and timing starts when the PTT switch is released. If
the PTT switch is pressed during the penalty time, the
time-out indication occurs again and the transmitter
17
May 2002
Part No. 002-5100-100